Dry electrode and dry battery comprising same

Abstract

The utility model discloses a dry electrode which comprises a dry-method positive electrode active material layer, a dry-method negative electrode active material layer and a tab, the periphery of the dry-method positive electrode active material layer is coated with a diaphragm, a PET composite foil current collector is arranged between the dry-method positive electrode active material layer and the dry-method negative electrode active material layer, and the tab is arranged on the PET composite foil current collector; the utility model also discloses a dry battery comprising the dry electrode. The dry electrode provided by the utility model is non-toxic and harmless, low in cost and more in line with environmental protection requirements.

Description

Technical Field

[0001] The present application relates to the technical field of secondary batteries, and in particular to a dry electrode and a dry-process battery containing the same. Background Art

[0002] Dry electrode technology is a new type of battery manufacturing process that does not require the use of solvents to make electrodes, but directly coats the electrode material on metal foil. This technology has the advantages of high production efficiency, low cost, and environmental protection, and is considered to be an important development direction for future battery manufacturing.

[0003] With the popularity of electric vehicles, the demand for high-performance, low-cost batteries is increasing. Dry electrode technology can greatly improve the production efficiency and performance of batteries, reduce production costs, and is expected to promote the development of electric vehicles. Dry electrode technology can also improve the energy storage density and cycle life of energy storage systems, reduce the cost of energy storage systems, and help promote the application of energy storage systems. Dry electrode technology includes three steps: dry powder mixing, from powder to thin coating molding, to thin coating and current collector pressing, all three steps are solvent-free. Dry electrode technology has good adaptability and can be applied not only to current lithium-ion battery chemical systems, but also to future advanced new material systems, such as solid-state batteries.

[0004] In dry electrode technology, the fixation of the conductive material may be poor, which may lead to an unstable electrode structure and affect the long-term performance and stability of the electrode. The contact between the electrode material and the electrolyte is crucial for the electrochemical reaction. In dry electrodes, due to certain characteristics of the structure, there may be problems with poor contact between the electrode material and the electrolyte, which reduces the efficiency of the electrode. The mismatch between the thermal expansion coefficient of the material used in the electrode and other components may also cause structural problems when the temperature changes. This may cause deformation or cracking of the electrode, which in turn affects the performance of the electrode. Improving these shortcomings requires in-depth research and technological innovation to improve the performance and feasibility of dry electrode technology. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides a dry electrode and a dry-process battery containing the same, which is non-toxic and harmless, low in cost, and more in line with environmental protection requirements.

[0006] The technical solution provided by the utility model is as follows:

[0007] A dry electrode comprises a dry positive electrode active material layer, a dry negative electrode active material layer and a tab, wherein the periphery of the dry positive electrode active material layer is coated with a diaphragm, a PET composite foil current collector is arranged between the dry positive electrode active material layer and the dry negative electrode active material layer, and the tab is arranged on the PET composite foil current collector.

[0008] Preferably, the PET composite foil current collector comprises a PET composite aluminum foil layer, a PET composite copper foil layer and a PET film layer, one side of the PET composite aluminum foil layer is connected to the dry-process positive electrode active material layer, and the other side is connected to the PET composite copper foil layer, one side of the PET composite copper foil layer is connected to the dry-process negative electrode active material layer, and the PET film layer is arranged between the PET composite aluminum foil layer and the PET composite copper foil layer.

[0009] Preferably, the thickness of the PET composite aluminum foil layer is 6-8 μm.

[0010] Preferably, the thickness of the PET composite copper foil layer is 2-4 μm.

[0011] Preferably, the thickness of the PET film layer is 1-5 μm.

[0012] Preferably, there are two electrode tabs, which are respectively fixedly connected to two sides of the PET composite foil current collector.

[0013] Preferably, the PET composite foil current collector comprises a coating area and a hollow foil area.

[0014] A dry-process battery comprises the above-mentioned dry electrode, electrolyte, diaphragm and outer shell, wherein the dry electrode, electrolyte and diaphragm are respectively arranged in the outer shell.

[0015] Preferably, the outer shell has a thickness of 1.5-5 mm.

[0016] The present application has the following advantages over the prior art:

[0017] 1. The dry electrode and dry battery containing the same of the present application do not require liquid medium, which reduces energy loss and improves the energy efficiency of the electrode. Since there is no need to process a large amount of solution, energy consumption and cost are reduced. The dry electrode does not require a large amount of liquid container and can be designed into a lighter and more compact structure, which is conducive to integration and mobility in various applications. Since there is no liquid medium, the dry electrode is relatively less susceptible to external contaminants, which improves the stability and reliability of the electrode;

[0018] 2. The use of the dry electrode PET layer of the present application in the composite current collector can improve the combustion safety of the battery. By reducing the use of metal foil, it not only reduces the weight of the battery but also increases the energy density of the battery. In addition, the PET composite current collector also helps to reduce the shedding of active materials caused by the shrinkage of the metal foil, thereby increasing the cycle life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is a schematic diagram of the structure of the dry electrode in Example 1 of the utility model;

[0021] Figure 2 for Figure 1 Top view of the .

[0022] Reference numerals:

[0023] 1. Dry-process positive electrode active material layer; 2. Dry-process negative electrode active material layer; 3. Tab; 4. Diaphragm; 5. PET composite foil current collector; 51. PET composite aluminum foil layer; 52. PET composite copper foil layer; 53. PET film layer. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] like Figure 1 , 2 As shown, an embodiment of the utility model provides a dry electrode, including a dry positive electrode active material layer 1, a dry negative electrode active material layer 2 and a pole ear 3, the periphery of the dry positive electrode active material layer 1 is coated with a diaphragm 4, a PET composite foil current collector 5 is provided between the dry positive electrode active material layer 1 and the dry negative electrode active material layer 2, and the pole ear is arranged on the PET composite foil current collector 5.

[0026] In this embodiment, the dry-process positive electrode active material layer 1 includes lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, ternary materials, etc., but is not limited to these materials; and the dry-process negative electrode active material layer 2 includes artificial graphite, natural graphite, mesophase carbon microbeads, hard carbon, etc., and is also not limited to these.

[0027] In this embodiment, the PET composite foil current collector 5 adopts PET composite foil, which is lighter than traditional foil, so it can reduce the overall weight of the battery and improve the energy density of the battery, which is particularly important for application scenarios such as electric vehicles that require high energy density batteries. At the same time, it also has good heat resistance, electrical insulation and mechanical properties, making the PET composite foil safer during use. It can effectively prevent short circuits and overheating inside the battery, thereby improving the safety performance of the battery. PET composite foil can adapt to various battery chemical reactions, has good compatibility with electrolytes and other battery materials, and is conducive to improving the overall performance and stability of the battery.

[0028] In this embodiment, the diaphragm 4 can be made of various materials suitable for lithium-ion battery diaphragms in the art, including but not limited to one or more combinations of polytetrafluoroethylene, polyacrylonitrile, polyimide, polypropylene, polyvinylidene fluoride, aramid, etc.

[0029] In this embodiment, the PET composite foil current collector 5 includes a PET composite aluminum foil layer 51, a PET composite copper foil layer 52 and a PET film layer 53. The PET composite foil current collector 5 is prepared by magnetron sputtering and vacuum evaporation. One side of the PET composite aluminum foil layer 51 is connected to the dry-process positive electrode active material layer 1, and the other side is connected to the PET composite copper foil layer 52. One side of the PET composite copper foil layer 52 is connected to the dry-process negative electrode active material layer 2. The PET film layer 53 is arranged between the PET composite aluminum foil layer 51 and the PET composite copper foil layer 52.

[0030] In this embodiment, the thickness of the PET composite aluminum foil layer 5 is 6-8 μm. The thickness of the PET composite copper foil layer 5 is 2-4 μm. The thickness of the PET film layer is 1-5 μm. The PET composite foil current collector 5 includes a coating area and a blank foil area.

[0031] In this embodiment, the number of the electrode tabs 3 is two, and the two electrode tabs 3 are fixedly connected to the two sides of the PET composite foil current collector respectively.

[0032] A dry-process battery comprises the above-mentioned dry electrode, electrolyte, diaphragm and outer shell, wherein the dry electrode, electrolyte and diaphragm are respectively arranged in the outer shell.

[0033] In this embodiment, the thickness of the outer shell is 1.5-5 mm.

[0034] In this embodiment, the preparation method of the dry electrode is as follows:

[0035] S1. Fully mix the active material, conductive agent and thermoplastic material (the amount of electrode active material, conductive agent and polymer binder is 88% to 96%, 3% to 4% and 2% to 6% respectively) to form a uniform dry;

[0036] S2, using high-speed shearing treatment to fibrillate the mixture to obtain a fibrillated powder;

[0037] S3, rolling the fibrillated powder into a mold, cutting the broken powder at the edge to obtain an initial membrane (the thickness of the initial membrane is 100-150 μm);

[0038] S4, rolling the initial membrane to convert the initial membrane into a suitable electrode membrane (the thickness of the electrode membrane is 180-260 μm);

[0039] S5. The electrode membrane and the PET composite foil current collector 5 (one side is a PET composite aluminum foil layer 51, and the other side is a PET composite copper foil layer 52) are composited by hot rolling to obtain a dry electrode sheet.

[0040] The dry electrode of this embodiment is prepared by a dry process, and has a higher compaction density, which is beneficial to improving the energy density of the battery. In addition, the dry process can also improve the consistency of the electrode and increase the cycle life of the battery.

[0041] In this embodiment, the formation methods of the dry-process positive electrode active material layer 1 and the dry-process negative electrode active material layer 2 are both hot pressing, the temperature is 90-140°C, and the hot pressing pressure is 50-120N. The connection methods of the PET composite foil current collector 5 and the dry-process positive electrode active material layer 1 and the dry-process negative electrode active material layer 2 are both hot roller pressing, the temperature is 60-80°C, and the hot pressing pressure is 50-120N.

[0042] The dry electrode of this embodiment can be used in power batteries.

[0043] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dry electrode, comprising a dry positive electrode active material layer (1), a dry negative electrode active material layer (2) and a tab (3), characterized in that: The periphery of the dry-process positive electrode active material layer (1) is coated with a separator (4), a PET composite foil current collector (5) is provided between the dry-process positive electrode active material layer (1) and the dry-process negative electrode active material layer (2), and the electrode tab (3) is provided on the PET composite foil current collector (5).

2. The dry electrode according to claim 1, characterized in that The PET composite foil current collector (5) comprises a PET composite aluminum foil layer (51), a PET composite copper foil layer (52) and a PET film layer (53); one side of the PET composite aluminum foil layer (51) is connected to the dry-process positive electrode active material layer (1), and the other side is connected to the PET composite copper foil layer (52); one side of the PET composite copper foil layer (52) is connected to the dry-process negative electrode active material layer (2); and the PET film layer (53) is arranged between the PET composite aluminum foil layer (51) and the PET composite copper foil layer (52).

3. The dry electrode according to claim 2, characterized in that The thickness of the PET composite aluminum foil layer (51) is 6-8 μm.

4. The dry electrode according to claim 2, characterized in that The thickness of the PET composite copper foil layer (52) is 2-4 μm.

5. The dry electrode according to claim 2, characterized in that: The thickness of the PET film layer (53) is 1 to 5 μm.

6. The dry electrode according to any one of claims 1 to 4, characterized in that: The number of the electrode tabs (3) is two, and the two electrode tabs (3) are respectively fixedly connected to two sides of the PET composite foil current collector (5).

7. The dry electrode according to any one of claims 1 to 4, characterized in that: The PET composite foil current collector (5) comprises a coating area and a hollow foil area.

8. A dry-process battery, characterized in that: It comprises a dry electrode, an electrolyte, a diaphragm and an outer shell as described in any one of claims 1 to 7, wherein the dry electrode, the electrolyte and the diaphragm are respectively arranged in the outer shell.

9. The dry-process battery according to claim 8, characterized in that: The thickness of the outer shell is 1.5-5 mm.

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